A continuous preparation method for antibacterial and antioxidant carbon quantum dots

Abstract

The present invention discloses a continuous preparation method for antibacterial and antioxidant carbon quantum dots. The preparation method comprises the following steps: completely dissolving ascorbic acid and polyethyleneimine in deionized water to obtain a raw material solution, and controlling the pressurized solvent thermal reaction flow rate of the mixed solution in the pipeline by an injection pump to obtain antibacterial and antioxidant positively charged carbon quantum dots. The present invention creatively applies a microfluidic method to successfully prepare positively charged carbon dots using high-quality and inexpensive carbon sources, ascorbic acid and polyethyleneimine. The preparation process is simple, the cost is low, and a large amount of carbon quantum dot solution can be produced and stored in a single batch. The prepared carbon quantum dots have excellent water solubility and biocompatibility, and are widely applicable. They can be loaded on a hydrogel and applied to a skin wound to accelerate wound healing.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical nanomaterials, and in particular to a continuous preparation method of antibacterial and antioxidant carbon quantum dots and applications thereof. Background Art

[0002] The skin is the largest organ in the body, serving as a barrier against external stimuli and damage. When damaged, the skin loses its protective barrier function and is easily invaded by pathogenic microorganisms, causing bacterial infection and delaying wound healing, posing a serious threat to human health. Wound infection is often accompanied by an inflammatory response, which induces the production of hydrogen peroxide (H2O2), hydroxyl radicals (·OH), and superoxide anion radicals (O2 ·- ) and other reactive oxygen species (ROS), leading to a strong oxidative stress response, destroying proteins and damaging normal cells. Developing treatments to promote wound repair based on this has important practical significance.

[0003] In recent years, carbon quantum dots have become an emerging fluorescent carbon nanomaterial due to their simple preparation process, excellent optical properties, low toxicity, and excellent biocompatibility. Carbon quantum dots utilize their positively charged surface functional groups, nanometer size, and large surface area to bind to negatively charged bacterial cell membranes through electrostatic attraction, disrupting the bacterial membrane while simultaneously entering the cell and leaking the cytoplasm, ultimately killing the bacteria. Furthermore, carbon quantum dots inhibit excess reactive oxygen species by scavenging free radicals.

[0004] In summary, carbon quantum dots have broad application prospects in biomedical fields such as antibacterial and antioxidant. It is of great practical significance to develop a safe, biocompatible, low-cost and high-yield carbon quantum dot preparation method. Summary of the Invention

[0005] The present invention aims to provide a method for preparing positively charged carbon quantum dots with antibacterial and antioxidant properties based on their properties. This method utilizes readily available raw materials, is simple to operate, and employs mild and controllable reaction conditions, enabling continuous, large-scale production of carbon quantum dots.

[0006] The method for preparing a continuous high quantum yield fluorescent carbon quantum dot according to the present invention comprises the following steps:

[0007] Step 1: Add ascorbic acid and polyethyleneimine to ethanol in the appropriate proportions and stir thoroughly until a clear, homogeneous solution is formed. The ascorbic acid concentration range is 0.1-0.5 g / L, and the polyethyleneimine concentration is controlled between 5-500 g / L.

[0008] Step 2: Using a syringe pump to control the flow rate of the mixed solution in the pipeline;

[0009] Step 3: Obtaining a carbon quantum dot solution by performing a solvothermal reaction in the pipeline;

[0010] Step 4: dialyzing the carbon quantum dot solution obtained in step 3, filtering it through a filter membrane, concentrating it by rotary evaporation, and freeze-drying it to obtain a carbon quantum dot powder with antibacterial and antioxidant properties;

[0011] Step 5: The carbon quantum dot powder obtained in step 4 was dissolved in an aqueous solution to obtain a carbon quantum dot solution with a concentration of 1 mg / mL, and the solution was doped into a hydrogel and applied to the wound surface of mice to accelerate wound healing.

[0012] Furthermore, the flow rate of the mixed solution in the pipeline described in step 2 is 1 to 10 mL / min;

[0013] Furthermore, the pipe described in step 3 has a length of 10 to 15 m, a wall thickness of 1 to 1.5 mm, and an inner diameter of 1 to 1.5 mm;

[0014] Furthermore, the reaction temperature in step 3 is 160-200°C;

[0015] Furthermore, the molecular weight cut-off of the dialysis bag in step 4 is 500 Da, and the dialysis time is 12 to 36 h;

[0016] Furthermore, the pore size of the filter membrane in step 4 is 0.22 μm

[0017] Furthermore, in step 5, the carbon quantum dot solution in the hydrogel accounts for 1 to 3 wt % of the hydrogel.

[0018] The beneficial effects of the present invention are as follows:

[0019] 1. The present invention provides a continuous preparation method for antibacterial and antioxidant carbon quantum dots. This method innovatively utilizes microfluidics to successfully produce carbon quantum dots using high-quality and inexpensive carbon sources: ascorbic acid and polyethyleneimine. The preparation process is simple, low-cost, and has demonstrated significant efficacy in practical medical applications. Large quantities of carbon quantum dot solutions can be produced and stored in a single batch, and the reaction state of the carbon quantum dots can be monitored and adjusted in real time. The preparation process is simple, and production and analysis costs are low.

[0020] 2. The carbon quantum dots prepared by the present invention have excellent water solubility and biocompatibility, as well as excellent antibacterial and antioxidant properties. They have a wide range of applications and can be loaded into hydrogels and applied to skin wounds to accelerate wound healing. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the process flow of the device; 1-injection pump, 2-oven, 3-check valve, 4-cooling liquid tank, 5-finished product collector;

[0022] Figure 2 Transmission electron microscopy image of carbon quantum dots prepared in Example 1;

[0023] Figure 3 A photograph showing the antibacterial effect of carbon quantum dots prepared in Example 3 on Staphylococcus aureus;

[0024] Figure 4 DPPH scavenging rate of different concentrations of carbon quantum dots prepared for implementation case 6;

[0025] Figure 5 ·OH scavenging rates of different concentrations of carbon quantum dots prepared for implementation case 6;

[0026] Figure 6 Photo of the wound healing effect of the carbon quantum dot hydrogel dressing prepared for implementation case 6 on mice, with a scale of 0.5 cm.

[0027] Specific implementation examples

[0028] The following provides a clear and complete description of the technical solutions in the examples of the present invention. Obviously, the examples described are only some examples of the present invention, not all examples. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0029] The following experimental methods and detection methods, unless otherwise specified, are conventional methods; the following reagents and raw materials, unless otherwise specified, are commercially available.

[0030] Example 1

[0031] Step 1: Dissolve 0.002 g of ascorbic acid and 10 g of polyethyleneimine in 20 mL of ethanol to obtain a transparent and uniform solution;

[0032] Step 2: The mixed solution prepared in step 1 was added to the pipeline at a flow rate of 10 mL / min using a syringe pump;

[0033] Step 3: A carbon quantum dot solution is obtained by performing a solvothermal reaction in a pipe at 160°C;

[0034] Step 4: The carbon quantum dot solution obtained in step 3 is dialyzed for 12 hours, then filtered through a filter membrane, concentrated by rotary evaporation, and freeze-dried to obtain a carbon quantum dot powder with antibacterial and antioxidant properties;

[0035] Step 5: The carbon quantum dot powder obtained in Step 4 was dissolved in an aqueous solution to obtain a 1 mg / mL carbon quantum dot solution. This solution was then incorporated into a hydrogel at a 1 wt% concentration and applied to the wound surface of the mouse. Wound healing was observed. Results showed that, starting on day 4, excessive inflammation during the wound diffusion phase inhibited wound healing. By day 12, the wound was almost completely healed.

[0036] Example 2

[0037] Step 1: Dissolve 0.01 g of ascorbic acid and 1 g of polyethyleneimine in 20 mL of ethanol to obtain a transparent and uniform solution;

[0038] Step 2: The mixed solution prepared in step 1 was added to the pipe using a syringe pump to control the flow rate of the mixed solution at 2 mL / min;

[0039] Step 3: A carbon quantum dot solution is obtained by performing a solvothermal reaction in a pipe at 170°C;

[0040] Step 4: The carbon quantum dot solution obtained in step 3 is dialyzed for 12 hours, then filtered through a filter membrane, concentrated by rotary evaporation, and freeze-dried to obtain a carbon quantum dot powder with antibacterial and antioxidant properties;

[0041] Step 5: The carbon quantum dot powder obtained in Step 4 was dissolved in an aqueous solution to obtain a 1 mg / mL carbon quantum dot solution. This solution was then doped into a hydrogel at a 2 wt% concentration and applied to the wound surface of the mouse. Wound healing was observed, and the results showed that, starting on day 4, excessive inflammation during the wound diffusion phase inhibited wound healing. By day 12, the wound was almost completely healed.

[0042] Example 3

[0043] Step 1: Dissolve 0.01 g of ascorbic acid and 8 g of polyethyleneimine in 20 mL of ethanol to obtain a transparent and uniform solution;

[0044] Step 2: The mixed solution prepared in step 1 was added to the pipe using a syringe pump to control the flow rate of the mixed solution at 2 mL / min;

[0045] Step 3: A carbon quantum dot solution is obtained by performing a solvothermal reaction in a pipe at 170°C;

[0046] Step 4: The carbon quantum dot solution obtained in step 3 is dialyzed for 12 hours, then filtered through a filter membrane, concentrated by rotary evaporation, and freeze-dried to obtain a carbon quantum dot powder with antibacterial and antioxidant properties;

[0047] Step 5: The carbon quantum dot powder obtained in Step 4 was dissolved in an aqueous solution to obtain a 1 mg / mL carbon quantum dot solution. This solution was then incorporated into a hydrogel at a 3 wt% concentration and applied to the wound surface of the mouse. Wound healing was observed, and the results showed that, starting on day 4, excessive inflammation during the wound diffusion phase inhibited wound healing. By day 12, the wound was almost completely healed.

[0048] Example 4

[0049] Step 1: Dissolve 0.0045 g of ascorbic acid and 10 g of polyethyleneimine in 20 mL of ethanol to obtain a transparent, homogeneous solution.

[0050] Step 2: The mixed solution prepared in step 1 was added to the pipe using a syringe pump to control the flow rate of the mixed solution at 1 mL / min;

[0051] Step 3: Obtaining a carbon quantum dot solution by performing a solvothermal reaction in a pipe at 200°C;

[0052] Step 4: The carbon quantum dot solution obtained in step 3 is dialyzed for 12 hours, then filtered through a filter membrane, concentrated by rotary evaporation, and freeze-dried to obtain a carbon quantum dot powder with antibacterial and antioxidant properties;

[0053] Step 5: The carbon quantum dot powder obtained in Step 4 was dissolved in an aqueous solution to obtain a 1 mg / mL carbon quantum dot solution. This solution was then doped into a hydrogel at a 2 wt% concentration and applied to the wound surface of the mouse. Wound healing was observed, and the results showed that, starting on day 4, excessive inflammation during the wound diffusion phase inhibited wound healing. By day 12, the wound was almost completely healed.

[0054] Example 5

[0055] Step 1: Dissolve 0.0065 g of ascorbic acid and 10 g of polyethyleneimine in 20 mL of ethanol to obtain a transparent, homogeneous solution.

[0056] Step 2: The mixed solution prepared in step 1 was added to the pipe using a syringe pump to control the flow rate of the mixed solution at 5 mL / min;

[0057] Step 3: A carbon quantum dot solution is obtained by performing a solvothermal reaction in a pipe at 180°C;

[0058] Step 4: The carbon quantum dot solution obtained in step 3 is dialyzed for 36 hours, then filtered through a filter membrane, concentrated by rotary evaporation, and freeze-dried to obtain a carbon quantum dot powder with antibacterial and antioxidant properties;

[0059] Step 5: The carbon quantum dot powder obtained in Step 4 was dissolved in an aqueous solution to obtain a 1 mg / mL carbon quantum dot solution. This solution was then incorporated into a hydrogel at a 3 wt% concentration and applied to the wound surface of the mouse. Wound healing was observed, and the results showed that, starting on day 4, excessive inflammation during the wound diffusion phase inhibited wound healing. By day 12, the wound was almost completely healed.

[0060] Example 6

[0061] Step 1: Dissolve 0.01 g of ascorbic acid and 5 g of polyethyleneimine in 20 mL of ethanol to obtain a transparent and uniform solution;

[0062] Step 2: The mixed solution prepared in step 1 was added to the pipe using a syringe pump to control the flow rate of the mixed solution at 1 mL / min;

[0063] Step 3: A carbon quantum dot solution is obtained by performing a solvothermal reaction in a pipe at 190°C;

[0064] Step 4: The carbon quantum dot solution obtained in step 3 is dialyzed for 24 hours, then filtered through a filter membrane, concentrated by rotary evaporation, and freeze-dried to obtain a carbon quantum dot powder with antibacterial and antioxidant properties;

[0065] Step 5: The carbon quantum dot powder obtained in Step 4 was dissolved in an aqueous solution to obtain a 1 mg / mL carbon quantum dot solution. This solution was then incorporated into a hydrogel at a 3 wt% concentration and applied to the wound surface of the mouse. Wound healing was observed, and the results showed that, starting on day 4, excessive inflammation during the wound diffusion phase inhibited wound healing. By day 12, the wound was almost completely healed.

[0066] Example 7

[0067] Step 1: Dissolve 0.002 g of ascorbic acid and 10 g of polyethyleneimine in 20 mL of ethanol to obtain a transparent and uniform solution;

[0068] Step 2: The mixed solution prepared in step 1 was added to the pipeline at a flow rate of 10 mL / min using a syringe pump;

[0069] Step 3: Obtaining a carbon quantum dot solution by performing a solvothermal reaction in a pipe at 200°C;

[0070] Step 4: The carbon quantum dot solution obtained in step 3 is dialyzed for 12 hours, then filtered through a filter membrane, concentrated by rotary evaporation, and freeze-dried to obtain a carbon quantum dot powder with antibacterial and antioxidant properties;

[0071] Step 5: The carbon quantum dot powder obtained in Step 4 was dissolved in an aqueous solution to obtain a 1 mg / mL carbon quantum dot solution. This solution was then doped into a hydrogel at a 2 wt% concentration and applied to the wound surface of the mouse. Wound healing was observed, and the results showed that, starting on day 4, excessive inflammation during the wound diffusion phase inhibited wound healing. By day 12, the wound was almost completely healed.

[0072] Example 8

[0073] Step 1: Dissolve 0.01 g of ascorbic acid and 1 g of polyethyleneimine in 20 mL of ethanol to obtain a transparent and uniform solution;

[0074] Step 2: The mixed solution prepared in step 1 was added to the pipe at a flow rate of 3 mL / min using a syringe pump;

[0075] Step 3: A carbon quantum dot solution is obtained by performing a solvothermal reaction in a pipe at 160°C;

[0076] Step 4: The carbon quantum dot solution obtained in step 3 is dialyzed for 12 hours, then filtered through a filter membrane, concentrated by rotary evaporation, and freeze-dried to obtain a carbon quantum dot powder with antibacterial and antioxidant properties;

[0077] Step 5: The carbon quantum dot powder obtained in Step 4 was dissolved in an aqueous solution to obtain a 1 mg / mL carbon quantum dot solution. This solution was then doped into a hydrogel at a 2 wt% concentration and applied to the wound surface of the mouse. Wound healing was observed, and the results showed that, starting on day 4, excessive inflammation during the wound diffusion phase inhibited wound healing. By day 12, the wound was almost completely healed.

[0078] The wound healing effect of the carbon quantum dots prepared by the present invention is as follows Figure 6 As shown in the figure, it can be seen that after treatment with carbon quantum dots, the wound recovery speed of mice was effectively optimized, and Figure 4 、 Figure 5 It can be clearly seen that the carbon quantum dots prepared by the present invention have excellent inhibitory and elimination functions on excess reactive oxygen species. The above facts and results indicate that the carbon quantum dots of the present invention have good biocompatibility and huge application potential.

[0079] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A continuous preparation method of antibacterial and antioxidant carbon quantum dots, characterized in that: The following steps are involved: Step 1: Add ascorbic acid and polyethyleneimine to ethanol in proportion and stir thoroughly until a clear and uniform solution is formed. The ascorbic acid concentration ranges from 0.1 to 0.5 g / L, and the polyethyleneimine concentration is controlled at 5 to 500 g / L. Step 2: Using a syringe pump to control the flow rate of the mixed solution in the pipeline; Step 3: Obtaining a carbon quantum dot solution by performing a solvothermal reaction in the pipeline; Step 4: Filter the carbon quantum dot solution obtained in step 3 through a filter membrane, then dialyze, concentrate by rotary evaporation, and freeze-dry to obtain carbon quantum dot powder with antibacterial and antioxidant properties; Step 5: Dissolve the carbon quantum dot powder obtained in step 4 in water to obtain a carbon quantum dot solution with a concentration of 1 mg / mL, and dope it into the hydrogel.

2. The preparation method according to claim 1, wherein The flow rate of the mixed solution described in step 2 is controlled by adjusting the syringe pump, and the flow rate is 1-10 mL / min.

3. The preparation method according to claim 1, wherein The pipe described in step 3 has a length of 10 to 15 m, a wall thickness of 1 to 1.5 mm, and an inner diameter of 1 to 1.5 mm.

4. The preparation method according to claim 1, characterized in that The reaction temperature in step 3 is 120-200°C.

5. The preparation method according to claim 1, characterized in that In the hydrogel in step 5, the amount of the carbon quantum dot solution added accounts for 1 to 3 wt % of the total mass of the hydrogel.

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